Make helper functions static. NFC.

llvm-svn: 245549
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index f38360e..6e633cc 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -518,7 +518,7 @@
 /// \returns Optional value, holding the RolledDynamicCost and UnrolledCost. If
 /// the analysis failed (no benefits expected from the unrolling, or the loop is
 /// too big to analyze), the returned value is None.
-Optional<EstimatedUnrollCost>
+static Optional<EstimatedUnrollCost>
 analyzeLoopUnrollCost(const Loop *L, unsigned TripCount, DominatorTree &DT,
                       ScalarEvolution &SE, const TargetTransformInfo &TTI,
                       int MaxUnrolledLoopSize) {